A comparison between Complement Fixatlon Test and Chagas-Látex Antigen performed in: a) 902 serum samples from an evidemiological survey; b) 131 serum samples from hospitalized patients; c) 90 serum samples from hospitalized patients and relatives, showed low co-positivity index, being respectively: a) = 0,6119; b) = 0,7704; c) = 0,6721. A comparison between Hemoaglutination Test and Chagas-Látex Antigen in 90 serum samples of c) grup showed also a low co-positivity index: 0,7222. The authors conclude that Chagas-Látex Antigen, owing to its low sensibility rate, is hardly indicated for diagnostic purposes either in epidemiological survef areas or in hospitalized patients.